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Biomedical subjects

G R May

Publications and source records attributed to G R May.

50 records · Page 3Linked to original sources
PubMed1985

Bone tumors: magnetic resonance imaging versus computed tomography.

The magnetic resonance (MR) imaging characteristics of bone tumors are described and the clinical utility of MR imaging in patient evaluation is reported. Fifty-two patients with skeletal lesions were examined with a Picker MR imager (0.15-T resistive magnet). Twenty-five patients had primary malignancies, seven had benign bone neoplasms, 15 had skeletal metastases, and five had neoplasm simulators. Forty-five patients had CT scans available for comparison. For demonstrating the extent of tumor in marrow, MR was superior to CT in 33% of cases, about equal to CT in 64%, and inferior to CT in 2%. For delineating the extent of tumor in soft tissue, MR was superior to CT in 38% of cases and about equal to CT in 62%. CT was superior in all cases for demonstrating calcific deposits and pathologic fractures. In four patients with metal prostheses or surgical clips, MR was superior to CT in documenting recurrent tumor because of artifactual degradation of the CT image. Direct sagittal and coronal images from MR permit accurate assessment of the relationship of tumor to adjacent normal structures, including the physis, joints, and neurovascular structures. MR is useful in the evaluation of bone tumors: it is of greatest value in evaluations of the peripheral skeleton, the medullary canal, soft tissues, and postoperative tumor recurrence. With a 0.15-T magnet, MR is less useful in the evaluation of the axial skeleton and cortical bone.

Aged↗
PubMed1985

Cholangiocarcinoma complicating primary sclerosing cholangitis: cholangiographic appearances.

Cholangiograms from 104 patients (and serial cholangiograms in 66 patients) with primary sclerosing cholangitis (PSC) were reviewed. In 13 patients the additional diagnosis of cholangiocarcinoma was made at biopsy or autopsy. Cholangiograms from patients with both PSC and carcinoma were compared with cholangiograms from patients with PSC alone. Marked dilatation of ducts or ductal segments (100% vs. 24%) and the appearance of a polypoid mass (46% vs. 7%) were common findings in the group of patients whose disease was complicated by malignancy. In the malignant group, polypoid masses were larger, measuring 1 cm or greater in diameter. On serial cholangiograms, four of 15 patients with progressive stricture formation and four of five with progressive ductal dilatation proved to have carcinomas. The frequent occurrence of bile duct carcinoma as a complication of PSC in this group of patients indicates that PSC has a strong tendency to undergo malignant degeneration. Cholangiographic findings which suggest malignant degeneration include markedly dilated ducts or ductal segments, presence of a polypoid mass 1 cm or greater in diameter, and progressive stricture formation or ductal dilatation.

Adenoma, Bile Duct↗
PubMed1985

Focal nodular hyperplasia and hepatic adenoma: comparison of angiography, CT, US, and scintigraphy.

The authors reviewed 23 cases of focal nodular hyperplasia and 13 cases of hepatic adenoma, all of which were confirmed pathologically. All solitary masses that exhibited normal or increased uptake of technetium 99m-sulfur colloid were shown to be hyperplasia; while previous criteria such as a central blood supply on angiograms or a central scar on computed tomography (CT) or ultrasound (US) scans were helpful, they were relatively infrequent. A mass that was slightly hypodense and homogeneous on a CT or US scan and highly vascular with an intense capillary stain on an angiogram was almost always hyperplasia. Acute hemorrhage within a focal hepatic tumor was common in adenoma but did not occur in hyperplasia.

Adenoma↗
PubMed1985

Percutaneous removal of small ureteral calculi.

Percutaneous renal and ureteral stone removal procedures are widely practiced. A new technique is described for removal of small symptomatic ureteral calculi using small (less than or equal to 14 French) tearable sheaths and standard stone retrieval baskets placed through acute percutaneous nephrostomy tracks. This fluoroscopically-guided technique was successful in 60 of 64 patients, who ranged from 16 to 88 years old. Subsequent endoscopic percutaneous calculus removal was successful in the four failures. The use of these small sheaths over previously described large tracks has produced no major complications, short hospital stays, and minimal patient disability.

Humans↗
PubMed1985

Nonoperative dilatation of dominant strictures in primary sclerosing cholangitis.

While most cases of primary sclerosing cholangitis are characterized by multifocal bile duct strictures, a few have a localized high-grade stricture (dominant stricture) superimposed on diffuse disease. This dominant stricture may cause jaundice or bacterial cholangitis in some patients. Dominant strictures were percutaneously dilated in 14 patients with primary sclerosing cholangitis and jaundice or bacterial cholangitis. Stricture dilatation produced a significant decrease in the frequency of cholangitis and a significant decrease in serum bilirubin in those with recent onset of jaundice. The only complication was bacteremia or cholangitis in five patients. Three of nine patients with successful dilatations developed recurrent strictures at 6-18 months. Balloon dilatation should be considered the treatment of choice for dominant strictures in symptomatic patients with primary sclerosing cholangitis who have recent onset of jaundice (less than 6 months' duration) or recurrent episodes of bacterial cholangitis.

Cholangiography↗
PubMed1984

Analysis of failure following curative irradiation of gallbladder and extrahepatic bile duct carcinoma.

Twenty patients with carcinoma of the gallbladder (GB-4 patients) or extrahepatic bile ducts (EHBD-16 patients) received radiation therapy with curative intent between January, 1980 and December, 1982. All 20 received 4500-5000 rad in 180-200 rad fractions to the tumor and regional lymph nodes. A 1000 to 1500 rad external beam boost was delivered in 180-200 rad fractions in 10 patients who received external beam alone or concomitant 5-Fluorouracil (5-FU). Three of the four GB and 5 of the 16 EHBD patients received a transcatheter boost with 192-Iridium (192Ir) to a dose of 2000-2500 rad calculated at a 0.5-0.1 cm radius. An additional 2 patients with EHBD lesions received an intraoperative electron (IORT) boost of 1500-2000 rad in one fraction calculated to the 90% isodose. Survival and patterns of failure were analyzed by site and treatment method. All four patients with GB carcinoma are dead of disease at 5 1/2, 6, 9 and 10 months from the date of diagnosis respectively. Three of the four developed diffuse peritoneal carcinomatosis. Five of the 16 patients with EHBD carcinoma are alive with a median follow-up of 18 months (range 6-23 months). Four of the 5 patients received a transcatheter 192Ir or IORT boost and all are without evidence of disease. Four of 9 patients who had a subtotal resection with transection of tumor, dilatation of the bile ducts with probes or curettement of the bile ducts developed either diffuse peritoneal carcinomatosis (3 patients) or a recurrence in the surgical scar (2 patients). Local failure was documented in 3 of the nine patients treated with external beam alone +/- 5-FU, and has been documented in one of the seven patients who received an IORT or transcatheter 192Ir boost. Further experience is necessary to determine whether this aggressive treatment will result in long-term disease-free survival in these patients.

Adult↗
PubMed1984

Magnetic resonance imaging of the chest: a diagnostic comparison with computed tomography and hilar tomography.

Computed tomography (with and without contrast enhancement) provides excellent diagnostic accuracy for the evaluation of the chest. Oblique (55 degrees) and anteroposterior hilar tomography is accurate for the evaluation of hilar nodes and masses. Magnetic resonance techniques provide excellent differentiation of vascular and nonvascular structures and therefore should be useful in the hilum and mediastinum. Magnetic resonance imaging was used in 55 patients with known pathologic conditions in the mediastinum, hilum, and lungs to determine the accuracy and efficacy of this technique compared with computed and hilar tomography. The pathologic conditions included primary and metastatic neoplasms, benign masses, vascular abnormalities, and pulmonary nodules and infiltrates. Spatial resolution with magnetic resonance imaging is less than with computed tomography with our instrument (0.15 T resistive magnet). However, in the hilum and mediastinum, magnetic resonance imaging provided diagnostic information equal to that of computed tomography with contrast in 90% of patients. Vascular and nonvascular structures were more easily differentiated than with hilar tomography. Computed tomography was far superior in the evaluation of multiple pulmonary nodules. Lesions of the chest wall were better seen with magnetic resonance imaging because of the improved soft tissue contrast.

Adolescent↗
PubMed1984

Percutaneous nephrostomy for stone removal.

Percutaneous nephrostomy placement was performed in 700 patients as the initial procedure in renal or ureteral calculus removal. The ease or complexity of the subsequent calculus removal procedure is directly dependent on precise nephrostomy placement. The most important technical factors in nephrostomy placement for calculus removal are selection of the nephrostomy track course, the track entry site into the renal collecting systems, intrarenal catheter and guidewire manipulations, and the final catheter positioning across the ureteropelvic junction and down the ureter.

Catheters, Indwelling↗
PubMed1984

Rapid dilatation of percutaneous nephrostomy tracks.

Dilatation of a percutaneous nephrostomy track is essential for procedures such as stone or foreign-body removal and nephroscopy. In 140 patients, a technique was used of rapid dilatation to 24 French. It required only a few minutes. This procedure proved to be safe, easy to master, and the materials are readily available. Rapid track dilatation under general anesthesia, immediately followed by nephroscopy, has been a major contribution to success in renal calculus removal, resulting in considerably shortened patient and physician time.

Anesthesia, General↗
PubMed1984

Percutaneous ultrasonic lithotripsy.

Percutaneous ultrasonic lithotripsy, endoscopically guided calculus fragmentation and removal through a percutaneous track, is the most widely used technique in the United States for removal of symptomatic upper urinary tract calculi. This article reviews the establishment of percutaneous renal access, track dilatation, and stone removal methods that constitute this technique.

Humans↗
PubMed1983

Percutaneous lithotripsy.

We have performed percutaneous extractions of renal pelvic stones in 194 patients via the Wolf percutaneous universal nephroscope. At 1 session, with the patient under general anesthesia, a percutaneous tract is dilated to 24F and the stone is removed immediately. We have removed 185 stones successfully by ultrasonic lithotripsy, basket retrieval and/or use of forceps. Average operating time was 54 minutes and mean hospitalization was 5 days. The advantages of this technique are that a skin incision of only 1 cm. is required to remove the stone, hospital days are fewer than with open procedures and postoperative morbidity is minimal. In selected situations this method represents a significant advance over standard open surgical procedures for removal of renal pelvic stones.

Angiography↗
PubMed1981

Percutaneous biliary decompression: internal and external drainage in 50 patients.

A review of percutaneous biliary decompression performed at the Mayo Clinic was initiated to study indications, technique, technical problems, and short- and long-term complications. Data were collected on the initial 50 patients in whom biliary decompression had been performed. More than 80% of patients presented with lesions or a record of previous surgery near the ductal bifurcation that resulted in increased difficulty in obtaining internal drainage. Follow-up data were available in 40 patients and allowed careful evaluation of immediate and long-term complications. Significant complications were limited to intraabdominal bleeding, which occurred in four patients and resulted in death in one. Four patients experienced sepsis immediately after the procedure, and episodes of cholangitis occurred in seven patients who had long-term drainage catheters in place.

Adult↗
PubMedDate not supplied

Removal of stones from the bile duct at ERCP without sphincterotomy.

The main risks associated with endoscopic stone removal arise from the sphincterotomy that is performed to facilitate stone extraction. The complication rate may be higher when the bile duct is not dilated. Between January 30, 1990, and March 30, 1993, we attempted to remove stones up to 8 mm in diameter through the intact papilla, without performing sphincterotomy, in 24 patients. Nine patients underwent balloon dilation of the sphincter or of a low duct stricture to facilitate stone removal. All patients were treated successfully and are well at follow-up. Two patients (one having had balloon dilation of the sphincter) had mild pancreatitis that required 2 days in the hospital. During the same period, 215 patients were treated for duct stones 8 mm or less through a standard sphincterotomy. Complications occurred in 11 of these patients: five episodes of pancreatitis, three infections, one perforation, and two other complications. Although these two groups of patients are not directly comparable, it appears that selected stones can be extracted from the bile duct without sphincterotomy with relative safety. This technique should be studied further, especially in younger persons where sphincter preservation may be desirable.

Adolescent↗